Normative has specialized meanings in several academic disciplines. Generically, it means relating to an ideal standard or model. In practice, it has strong connotations of relating to a typical standard or model (see also normality).
For example, "children should eat vegetables", "smoking is bad", and "those who would sacrifice liberty for security deserve neither and will lose both" are normative claims. On the other hand, "vegetables contain a relatively high proportion of vitamins", "smoking causes cancer", and "a common consequence of sacrificing liberty for security is a loss of both" are positive claims. Whether or not a statement is normative is logically independent of whether it is verified, verifiable, or popularly held.
It is only with David Hume in the 18th century that philosophers began to take cognizance of the logical difference between normative and descriptive statements and thinking. There are several schools of thought regarding the status of normative statements and whether they can be rationally discussed or defended. Among these schools are the tradition of practical reason extending from Aristotle through Kant to Habermas, which asserts that they can, and the tradition of emotivism, which maintains that they are merely expressions of emotions and have no rational content.
Normative statements and norms, as well as their meanings, are an integral part of human life. They are fundamental for prioritizing goals and organizing and planning thought, belief, emotion and action and are the basis of much ethical and political discourse.
The way in which individuals or societies define that which they consider to be appropriate - that is: to be in accordance with their (normative) standards - varies greatly between peoples and cultures. Many philosophers have searched for a source of normative values which is independent of the individual's subjective morality and consequently objective and 'true' in nature.
In social sciences the term "normative" is used to describe the effects of those structures of culture which regulate the function of social activity. Those structures thus act to encourage or enforce social activity and outcomes that ought to (with respect to the norms implicit in those structures) occur, while discouraging or preventing social activity that ought not occur. That is, they promote social activity that is socially valued (see philosophy above). While there are always anomalies in social activity (typically described as "crime" or anti-social behaviour, see also normality) the normative effects of popularly-endorsed beliefs (such as "family values" or "common sense") push most social activity towards a generally homogeneous set, resulting in varying degrees of social stability.